The secret to living longer could be as simple as picking up your walking pace, according to a new study. Researchers from the University of Sydney found that walking at a brisk(快的) or fast pace was associated with a risk reduction of 24 percent for any cause of death.

This effect was even more obvious in older age group, with fast walkers over the age of 60 reducing their risk of death by a surprising 53 percent. Professor Emmanuel Stamatakis, who led the study, explained, “A fast pace is generally five to six kilometers per hour, but it really depends on a walker’s fitness levels; an alternatives indicator is to walk at a pace that makes you slightly out of breath or sweaty.”

In the study, the researchers looked at the results of 11 surveys from 1994 to 2008, in which participants recorded their walking pace, as well as age, sex and BMI. The analysis showed that walking at an average pace was associated with a 20 percent risk reduction for all-cause mortality(死亡率) compared with walking at a slow pace, while walking at a brisk or fast pace was associated with a risk reduction of 24 percent.

The researchers hope the findings will encourage the development of public health message about the benefits of walking pace. Professor Stamatakis added, “These analyses suggest that increasing walking pace may be a straightforward way for people to improve heart health and risk for premature mortality--- providing a simple message for public health campaigns to promote.

“Especially in situations when walking more isn’t possible due to time pressures or a less walking-friendly environment, walking faster may be a good option to get the heart rate up--- one that most people can easily add to their lives.”

In the thick jungle of New Guinea is nature’s most amazing theater, a Carola’s parotia (天堂鸟) is showing off his red and yellow feathers in a display called a “butterfly dance.”

This brilliantly colored birds of paradise have developed over millions of years from ancient birds whose feathers were dark and boring in comparison. It seems to be a contradiction (矛盾) that such extreme feathers and colors could have been favored by the process of evolution. After all, these same brightly colored feathers that attract mates also make the birds much more noticeable to predators (捕食者). The answer lies in the safe environment in which the birds live, and a process of evolution known as sexual selection. Except for other pressures, birds of paradise begin to specialize in attracting mates. Over millions of years they have slowly undergone changes in their colors, feathers and other talents. Characteristics that made one bird more attractive than another were passed on and impove over time.

In the past, demand for the bird’s feathers resulted in a huge amount of hunting. At the peak of the trade in the early 1900s, 80,000 skins a year were exported from New Guinea to Europe ladies’ hats. Nowadays, few birds die for fashion or for traditional costumes: Ceremonial feathers are passed down from generation to generation. Although local people are still permitted to hunt the birds for traditional uses, they usually target older male birds, leaving younger males to continue breeding.

David Mitchell, a conservationist, is relying on the help of local villagers to record where the birds display and what they eat. He hopes to not only gather data, but also encourage protection of the birds’ habitat. The strategy seems to be working. For millions of years, these impressive birds have danced to find their mates. They will keep dancing for as long as the forest offers them stage.

Baby seabirds that have not yet hatched communicate with their siblings (兄弟姐妹) in neighboring eggs by vibrating (震动) their shells (蛋壳), scientists have discovered.

A study of yellow-legged gulls revealed one of the known examples of embryo-to-embryo communication. When exposed to the alarm calls of an adult bird responding to a dangerous predator, developing chicks apparently were able to convey the presence of danger to their nest mates by vibrating inside their eggs.

The team collected 9 yellow-legged gull eggs from Sálvora Island and sorted them into nests of three. When the eggs were six days off hatching, two of the three eggs in each nest were temporarily removed from the nest and exposed to either a recording of a predator alarm call or white noise each day until the chicks hatched. The noise was delivered four times a day at random for three minutes at a time. The third egg from each group remained in the nest.

It was found that the embryos in the shells responded to the external alarm calls by vibrating and sounding less, and that this message appeared to be passed on to the third nestmate. It was seen to copy the vibrations. It experienced genetic changes and had an increase in the production of stress hormones (荷尔蒙) as well.

“This kind of communication—embryo to embryo—can generate developmental changes that can have potential benefits to the birds after hatching,” said Noguera, the lead author of the study.

A rise in stress hormones makes birds more aware of their surroundings after hatching. When hatched chicks were exposed to alarm sounds, it was found that those who had listened to the noises previously in the eggs were quicker to run away and hide.

Noguera said the phenomenon was likely to occur in other bird species. His team now plans to investigate whether the chicks are able to pick up other clues about their external environment before hatching, such as how many other eggs are in the nest.